P1630

DIAGNOSTIC TROUBLE CODES P1630, P1631
TCS active (test signal), no continuity or shorting to ground/batt+

Fault Symptom.
Marginal effect on emissions.

Condition
No test signal from the TCS in connection with starting or TCS active signal constantly high or pulses longer than 2.5 s.

Diagnostic Procedure.
1. Connect a Scan Tool.
Obtain readouts of the diagnostic trouble codes in the Motronic and TCS systems.

If diagnostic trouble codes B1406, B1407 or B1408 are stored in the TCS system, deal with them first. Then continue fault diagnosis in the Traction Control System. The above-mentioned diagnostic trouble codes also cause the TCS OFF indicator lamp to light up.

2. Start the engine and run it at idling speed.
Select "TCS".
Select "ACTIVATE".
Select "DISCONN ENRICHMENT".
The TCS sends positive battery voltage for disconnection of full-load enrichment. The Motronic system interprets this as fuel cut-off and the engine should stop.

If the command works, proceed to step 4.
If it does not, continue with step 3.

3. Check the lead between pin 38 of the Motronic control module and pin 21 of the TCS connector for continuity/shorting.

If the lead is OK, check the TCS control module's output signal on pin 21.

Connect a BOB.
Do not connect the Motronic control module.
Take a voltage reading across pins 14 and 38.
Select "TCS".
Select "ACTIVATE".
Select "DISCONN ENRICHMENT".
- In the "ON" position a reading of about 12 V should be obtained.
- In the "OFF" position a reading of about 0 V should be obtained.

If the voltage reading is OK, continue at "Procedure Before ECM Replacement". Component Tests
If it is not, continue in the Traction Control System.

4. Clear the diagnostic trouble code, drive the car on test to check whether the trouble code is generated afresh.

If the diagnostic trouble code is generated again, continue at "Procedure Before ECM Replacement". Component Tests
If the trouble code is not generated again the remedial measure taken was correct, otherwise the fault is of intermittent type.